In 1812 Havannah was ordered to the Adriatic, to reinforce the British squadron there that had already defeated the French forces in the area at several battles in 1811.

Havannah was based at the island of Lissa, but in 1813 Cadogan was ordered to operate against the Northern Italian coastline in conjunction with the approaching forces of the Austrian Empire during the War of the Sixth Coalition.

[4] Cadogan was highly successful in this endeavour, destroying or capturing numerous French and Italian ships off Vasto and other ports on the French-held coastline.

Cadogan took his seat in the House of Lords, but remained a prominent naval officer, continuing to rise in the service and serving as aide-de-camp to King William IV between 1830 and 1837 and Queen Victoria between 1837 and 1841.

As a naval captain in 1809 he had fought a duel with Lord Paget, who had seduced Cadogan's sister, Lady Charlotte.